%exm07421_1.m
clf,shg
x=3*pi*(-1:1/15:1);y=x;[X,Y]=meshgrid(x,y);
R=sqrt(X.^2+Y.^2)+eps;Z=sin(R)./R;
[dzdx,dzdy]=gradient(Z);
dzdr=sqrt(dzdx.^2+dzdy.^2);								%計算對r的全導(dǎo)數(shù)
dz2=del2(Z);													%計算曲率	<4>
figure(1)
subplot(1,2,1),surf(X,Y,Z),title('No. 1     surf(X,Y,Z)')
shading faceted,colorbar('horiz'),brighten(0.2)
subplot(1,2,2),surf(X,Y,Z,R),title('No. 2     surf(X,Y,Z,R)')
shading  faceted;colorbar('horiz')  

figure(2)
clf;subplot(1,2,1),surf(X,Y,Z,dzdx)
shading  faceted;brighten(0.1);colorbar('horiz')
title('No. 3     surf(X,Y,Z,dzdx)')
subplot(1,2,2),surf(X,Y,Z,dzdy)
shading  faceted;colorbar('horiz')
title('No. 4     surf(X,Y,Z,dzdy)')  

figure(3)
subplot(1,2,1),surf(X,Y,Z,abs(dzdr))
shading faceted;brighten(0.6);colorbar('horiz')
title('No. 5     surf(X,Y,Z,abs(dzdr))')
subplot(1,2,2),surf(X,Y,Z,abs(dz2))									%<17>
shading faceted;colorbar('horiz')
title('No. 6     surf(X,Y,Z,abs(dz2))')